@arges For me it's related at least part of it...
If I don't update the kernel to proposed-updates I have the following messages : If I use one CPU instead of two, I don't have those messages. BUG: soft lockup CPU#1 stuck for 22s! [qemu-system-x86:6889] INFO: rcu_sched detected stalls on CPUs/tasks: { 0} (detected by 1, t=15002 jiffies, g=5324, c=5323, q=0) BUG: soft lockup CPU#1 stuck for 22s! [qemu-system-x86:6889] ... My stress test is installing openstack with cloud-install on a single VM (nested KVM) generated with uvt-kvm and two vcpus. The backtrace I posted is the result of a manual "force off" (using virt-manager) of the test openstack VM. shortly after cloud-install tries to launch a VM in VM, the CPU reach 100% and all the shells (also console) get stuck The last kernel message of the VM before I loose control is "[ 942.295014] IPv6: ADDRCONF(NETDEV_UP): virbr0: link is not ready" -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1413540 Title: Trusty soft lockup issues with nested KVM To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1413540/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs